Regenerative medicine is an area of medicine that is concerned with the replacement or regeneration of human cells, tissues, or organs, in order to restore or establish normal functions. For example, stem cell therapies can be utilized in order to treat, prevent, or cure a variety of diseases and disorders.
Stem cells are cells that have the ability to divide without limit and that, under certain specific conditions, can differentiate into a variety of different cell types. Totipotent stem cells are stem cells that have the potential to generate all of the cells and tissues that make up an embryo. Pluripotent stem cells are stem cells that give rise to cells of the mesoderm, endoderm, and ectoderm. Multipotent stem cells are stem cells that have the ability to differentiate into two or more cell types, whereas unipotent stem cells are stem cells that differentiate into only one cell type. One type of such stem cells are mesenchymal stem cells. See, for example U.S. Patent Application US20190046576.
However, it is difficult to produce and store live stem cell-based therapies on a clinically relevant scale. (See, Trainor et al., Nature Biotechnology 32(1) (2014)). Moreover, the therapeutic potency and regenerative capacity of such therapies is often variable and the cells can die before or during transplantation. (See, Newell, Seminars in Immunopathology 33(2):91 (2011)). Implanted stem cells are also susceptible to host immune system attack and/or rejection, and it is often difficult to assess potency and/or control “dosing”. Thus, there is a need in the art for additional regenerative therapies that can overcome the cost, storage, and manufacturing quality control limitations that are currently associated with cell-based regenerative medicine therapies. In particular in the context of ocular conditions.
Blast and blunt injuries to the eye can cause a series of mechanical disruptions to the ocular contents including commotio retinae, traumatic cataract, disruption of the zonular attachments to the lens, angle recession, iris dialysis, and rupture of the pupillary sphincter. Treatment of these injuries has been limited to mechanical repair (when possible) of the iris, replacement of the crystalline lens with plastic lens implants, and repair of retinal detachments. There has been no treatment to repair the cellular architecture of the retina or the anterior chamber. Furthermore, traumatic optic neuropathy and optic nerve avulsion are among the six leading types of ocular injury that required specialized ophthalmic care during Operation Iraqi Freedom (Cho and Savitsky, “Ocular Trauma Chapter 7”, in Combat Casualty Care: Lessons learned from Oef and Oif, by Brian Eastbridge and Eric Savitsky, pp. 299-342, Ft. Detrick, Md.: Borden Institute (US) Government Printing Office, 2012), incorporated herein by reference in its entirety. Sixty percent of traumatic head injuries result in neuro-ophthalmic abnormalities (Van Stavern, et al., J Neuro-Ophthamol 21(2):112-117, 2001) (incorporated herein by reference in its entirety) half of which involve the optic nerves or visual pathways. Traumatic injury to neurons results in axonal damage and irreversible neuronal loss resulting in permanent deficits. While a number of potential neuroprotective therapies have been identified in animals, these single agents have generally failed to translate to therapies in human clinical trials (Turner, et al., J Neurosurg 118(5):1072-1085, 2013, incorporated herein by reference in its entirety). Combination therapies that affect several cellular targets are likely needed to prevent neuronal damage.
The cornea serves a protective role as the outermost tissue of the eye, however it is highly vulnerable to severe injury and disease. Its lack of blood vessels enables its transparency but also limits its ability to heal. Corneal injury, due to its potential to cause irreversible blindness, requires prompt intervention and aggressive treatment. The critical need for improved ocular surface healing therapies is particularly apparent for chemical burns and in severe corneal diseases, such as ocular manifestations of acute Chronic Graft v. Host Disease (GvHD), Stevens-Johnson Syndrome, Ocular Mucous Membrane Pemphigoid and other conditions giving rise to persistent corneal epithelial defect, which collectively comprise an incidence of over 100,000 cases per year. (See, Dietrich-Ntoukas et al. Cornea. 2012, 31(3):299-310; Stevenson W, et al., Clin Ophthalmol. 2013, 7:2153-2158.
White K D, et al., J Allergy Clin Immunol Pract. 2018; 6(1):38-69; Tauber J. (2002) Autoimmune Diseases Affecting the Ocular Surface. In: Ocular Surface Disease Medical and Surgical Management. Springer, New York, N.Y.; and Wirostko B, et al., Ocul Surf 2015 July; 13(3): 204-21; and Haring, R S., et al., JAMA Ophthalmol. 2016 Oct. 1; 134(10):1119-1124.)
Moreover, topical ophthalmic drug development is impeded by many anatomical constraints including tear turnover and dilution, nasolacrimal drainage, and reflex blinking with often less than 5% of the topically administered dose reaching deeper ocular tissues (Gaudana et al., 2009). In the case of corneal wounds, the initial insult causes rifts in the corneal epithelium thereby enabling the passage of topically applied MSC-S to penetrate the epithelial layers.
Accordingly, there is a large unmet need in the art for ocular therapies that can target the eye and deliver a therapeutic payload to difficult-to-reach sensory tissue which may have degenerated due to inflammation secondary to trauma (such as for example, burns, acute inflammation, age, and/or oxidative stress). The present invention meets this need by providing mesenchymal stem cell secretome compositions for use in such treatments, as well as methods for making such compositions.